The present invention is generally directed to toner compositions, and more specifically to encapsulated toner compositions and processes thereof. In one embodiment, the present invention is related to encapsulated toner compositions comprised of core components such as, for example, polymer resins, and colorants comprised of magnetic pigments, dyes, color pigments like cyan, magenta, yellow, red, green, blue, brown, or mixtures thereof, and thereover a polymeric shell containing a siloxane component. Another embodiment of the present invention relates to encapsulated toners comprised of a core containing a polymer resin, or plurality of polymer resins and magnetic pigment particles, such as iron oxides or magnetites, encapsulated within a polymeric shell, preferably comprised of a condensation polymer which has been chemically treated with a silane reagent. The encapsulated toners of the present invention in embodiments possess a number of advantages including cold pressure fixability, low heat fusibility, high image fix, excellent powder flow characteristics, excellent surface release properties, and excellent toner shelf stability.
Encapsulated toners and processes thereof are known. For example, both U.S. Pat. No. 4,626,489 and British Patent Publication 1,538,787 disclose similar processes for colored encapsulated toners wherein both the core resin and shell materials are prepared by free radical polymerization techniques. U.S. Pat. No. 4,565,764 discloses a colored microcapsule toner comprised of a colored core encapsulated by two resin shells with the inner shell having an affinity for both the core and the outer shell materials, and U.S. Pat. No. 4,254,201 illustrates the use of pressure sensitive toner clusters or aggregates with each granule of the cluster or aggregate being comprised of a pressure sensitive adhesive substance encapsulated by coating film. Color pigment particles or magnetic particles can be present on the surfaces of the encapsulated granules to impart the desired color to the toners. Also, U.S. Pat. No. 4,727,011 discloses a process for preparing encapsulated toners which involves a shell forming interfacial polycondensation and a core binder forming free radical polymerization, and further U.S. Pat. No. 4,708,924 discloses the use of a mixture of two polymers, one having a glass transition temperature in the range of -90.degree. C. to 5.degree. C., and the other having a softening temperature in the range of 25.degree. C. to 180.degree. C., as the core binders for a pressure fixable encapsulated toner. Other prior art, all U.S. patents, are summarized below: U.S. Pat. No. 4,339,518, which relates to a process of electrostatic printing with fluorinated polymer toner additives where suitable materials for the dielectric toner are thermoplastic silicone resins and fluorine containing resins having low surface energy, reference column 4, beginning at line 10, note for example the disclosure in column 4, line 16, through column 6; U.S. Pat. No. 4,016,099, which discloses methods of forming encapsulated toner particles and wherein there are selected organic polymers including homopolymers and copolymers such as vinylidene fluoride, tetrafluoroethylene, chlorotrifluoroethylene, and the like, see column 6, beginning at line 3, wherein there can be selected as the core materials polyolefins, polytetrafluoroethylene, polyethylene oxide and the like, see column 3, beginning at around line 18; U.S. Pat. No. 4,265,994 directed to pressure fixable capsule toners with polyolefins, such as polytetrafluoroethylene, see for example column 3, beginning at line 15; U.S. Pat. No. 4,497,885, which discloses a pressure fixable microcapsule toner comprising a pressure fixable component, a magnetic material, and other optional components, and wherein the core material can contain a soft material, typical examples of which include polyvinylidenefluoride, polybutadiene, and the like, see column 3, beginning at line 10; U.S. Pat. No. 4,520,091 discloses an encapsulated toner with a core which comprises a colorant, a dissolving solvent, a nondissolving liquid and a polymer, and may include additives such as fluorine containing resin, see column 10, beginning at line 27; U.S. Pat. No. 4,590,142 relating to capsule toners wherein additives such as polytetrafluoroethylenes are selected as lubricating components, see column 5, beginning at line 52; U.S. Pat. Nos. 4,599,289 and 4,803,144.
With further specific reference to the prior art, there are disclosed in U.S. Pat. No. 4,307,169 microcapsular electrostatic marking particles containing a pressure fixable core, and an encapsulating substance comprised of a pressure rupturable shell, wherein the shell is formed by an interfacial polymerization. One shell prepared in accordance with the teachings of this patent is a polyamide obtained by interfacial polymerization. Furthermore, there are disclosed in U.S. Pat. No. 4,407,922 pressure sensitive toner compositions comprised of a blend of two immiscible polymers selected from the group consisting of certain polymers as a hard component, and polyoctyldecylvinylether-co-maleic anhydride as a soft component. Interfacial polymerization processes are also selected for the preparation of the toners of this patent. Also, there are disclosed in the prior art encapsulated toner compositions containing costly pigments and dyes, reference for example the color photocapsule toners of U.S. Pat. Nos. 4,399,209; 4,482,624; 4,483,912 and 4,397,483.
In a patentability search report, there were recited the following U.S. patents: U.S. Pat. No. 4,565,733 wherein there is coated unencapsulated toners with a siloxane copolymer to impart clean up qualities thereof, see the Abstract for example; U.S. Pat. Nos. 4,640,881; 4,758,491; 4,876,169 and 4,954,408, which illustrate the inclusion of siloxane polymers in a toner binder resin; U.S. Pat. Nos. 4,585,723 and 4,902,570, which illustrate generally the coupling of siloxanes to small particles.
The disclosures of all the U.S. patents and other patent documents mentioned herein are totally incorporated herein by reference.
A number of copending applications illustrate various encapsulated toner compositions including, for example, U.S. Pat. Nos. 5,043,240, 5,035,970, 5,037,716, 5,139,915, 5,045,253 5,077,167, U.S. Ser. No. 546,278 U.S. Pat. No. 5,114,819, 5,082,757, U.S. Ser. No. 617,222, U.S. Pat. Nos. 5,023,159 5,013,630, 5,153,089, wherein there is disclosed, for example, a toner composition comprised of a homogeneous or substantially homogeneous mixture of polymer resin or resins, and color pigments, dyes, or mixtures thereof overcoated with a component derived from the condensation of a cellulose polymer with a silane component, the disclosures of each of the aforementioned copending applications and patents being totally incorporated herein by reference.